|Earthenware Pot 12 3/4 inches high (325mm).|
Another way to work is to squirt some underglaze into a saucer and apply it with a brush, or a sponge, or with what ever takes your fancy. You can dilute underglaze with water, and apply it in washes like watercolour. Some people spray diluted underglaze with an airbrush.
Thus far I have run some tests to see if the colours will be capable of firing to 1280 degrees Celsius (the bottles claim 1250+), and I have tried decorating on bisqued porcelain, on dry unfired porcelain, and on dry unfired earthenware that had a white slip over it. I have even tried some over a fired glaze.
|Earthenware lidded jar, 13 1/4 inches high (335mm).|
Working straight onto dry clay, or onto dry slip was the most creative and fun. The underglaze flows better from the brush on this surface, and it is also possible to scratch back through the underglaze into the pot. I did mess up technically a couple of times when applying underglaze over a slipped earthenware pot. After getting the underglaze too thick, I then got things too wet! When I worked back into some thick underglaze with water to try to smear it thinner, this caused the slip to start to bubble and lift. You have got to try these things though!
|Earthenware lidded jar, 14 inches high (355mm).|
I would have had great trouble trying to do tidy lines and squiggles that I was really in control of squirting it straight from the bottle; and applying it by brush in a confident manner would require many hours of practice. To start with, I fought the stuff, and tried to make it go where I wanted it to go, but later I started to enjoy working with the blobs, squirts, wiggles and smears that the bottle would make, and I started to like the hesitant, draggy line that the brush would make on the absorbent bisque or dry clay. I could tell the brush to do a circle, but the tip would drag and stutter, and limp round in a squarish shape, or spiral. It was fun!
After the underglaze decoration goes onto the pot then, you have guessed it, the glaze is applied. With care, this can sometimes be done straight away, or the pot can be bisque fired and the glaze applied by dipping, pouring, brushing or spraying.
The most obvious glaze to use over underglaze is a nice clear transparent one that shows the decoration that is beneath it. However, I can imagine all sorts of possibilities with coloured glazes, and semi translucent glazes, or no glaze at all on something sculptural in high fired porcelain.
*What brand of underglaze did I use? I used Kiwi underglaze (of course!!).